x86/acpi/cstate: Improve Intel Family model checks

Update the Intel Family checks to consistently use Family 15 instead of
Family 0xF. Also, get rid of one of last usages of x86_model by using
the new VFM checks.

Update the incorrect comment since the check has changed since the
initial commit:

  ee1ca48 ("ACPI: Disable ARB_DISABLE on platforms where it is not needed")

The two changes were:

 - 3e2ada5 ("ACPI: fix Compaq Evo N800c (Pentium 4m) boot hang regression")
   removed the P4 - Family 15.

 - 03a05ed ("ACPI: Use the ARB_DISABLE for the CPU which model id is less than 0x0f.")
   got rid of CORE_YONAH - Family 6, model E.

Signed-off-by: Sohil Mehta <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Acked-by: Dave Hansen <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: sohilmeh

arch/x86/include/asm/intel-family.h

@@ -187,6 +187,9 @@
 #define INTEL_XEON_PHI_KNL		IFM(6, 0x57) /* Knights Landing */
 #define INTEL_XEON_PHI_KNM		IFM(6, 0x85) /* Knights Mill */
 
+/* Notational marker denoting the last Family 6 model */
+#define INTEL_FAM6_LAST			IFM(6, 0xFF)
+
 /* Family 15 - NetBurst */
 #define INTEL_P4_WILLAMETTE		IFM(15, 0x01) /* Also Xeon Foster */
 #define INTEL_P4_PRESCOTT		IFM(15, 0x03)

arch/x86/kernel/acpi/cstate.c

@@ -13,6 +13,7 @@
 #include <linux/sched.h>
 
 #include <acpi/processor.h>
+#include <asm/cpu_device_id.h>
 #include <asm/cpuid.h>
 #include <asm/mwait.h>
 #include <asm/special_insns.h>
@@ -48,12 +49,11 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
 	/*
 	 * On all recent Intel platforms, ARB_DISABLE is a nop.
 	 * So, set bm_control to zero to indicate that ARB_DISABLE
-	 * is not required while entering C3 type state on
-	 * P4, Core and beyond CPUs
+	 * is not required while entering C3 type state.
 	 */
 	if (c->x86_vendor == X86_VENDOR_INTEL &&
-	    (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
-			flags->bm_control = 0;
+	    (c->x86 > 15 || (c->x86_vfm >= INTEL_CORE2_MEROM && c->x86_vfm <= INTEL_FAM6_LAST)))
+		flags->bm_control = 0;
 
 	if (c->x86_vendor == X86_VENDOR_CENTAUR) {
 		if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&